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UNIVERSITY  OF  ILLINOIS 

Agricultural  Experiment  Station 


BULLETIN  No.  291 


A  TECHNICAL  STUDY  OF  THE  DIGEST- 
IBILITY OF  CORN  STOVER  SILAGE 
FOR  BEEF  COWS 


BY  T.  S.  HAMILTON  AND  H.  P.  RUSK 


URBANA,  ILLINOIS,  MAY,  1927 


THE  more  practical  aspects  of  this  investigation, 
which  included  a  study  of  the  digestibility  of 
corn  stover  silage  for  beef  cows  and  also  a  de- 
termination of  the  metabolizable  energy  of  the  silage, 
are  as  follows: 

1.  Apparently  no  considerable  change  in  chemical 
composition  is  brought  about  by  ensiling  corn  stover. 

2.  The  availability  to  ruminants  of  the  nutrients 
in  corn  stover  silage  is  practically  the  same  as  that  of 
the  nutrients  in  ordinary  corn  stover. 

3.  There  is  about  85  percent  as  much  total  digesti- 
ble nutrients  in  stover  silage  as  there  is  in  the  same 
weight  of  whole  corn  silage;  however,  experimental 
feeding  trials  at  this  Station  indicate  that  in  practical 
feeding  stover  silage  is  only  about  two-thirds  as  valu- 
able as  normal  silage. 

4.  The  advantages  of  feeding  stover  silage  over 
ordinary  stover  from  the  shock  or  pasturing  in  the 
fields  are  (1)  reduction  of  loss  of  material  from  ex- 
posure to  rain  and  wind;  (2)  no  loss  from  tramping; 
(3)  an  increased  palatability,  causing  a  greater  con- 
sumption and  smaller  waste  in  feeding  due  to  the  fact 
that  stalks  have  been  softened,  broken  up,  made  juicy 
and  palatable;  (4)  a  much  greater  ultimate  utilization 
of  the  nutrients  of  the  corn  crop  than  when  the  stover 
is  fed  from  the  shock  or  is  pastured  in  the  field. 

5.  The  ensiling  of  stover  offers  a  method  of  util- 
izing the  by-products  of  corn  culture  in  an  effective 
and  economical  way  without  limiting  the  utilization 
of  the  main  product,  the  grain. 


A  TECHNICAL  STUDY  OF  THE  DIGEST- 
IBILITY OF  CORN  STOVER  SILAGE 
FOR  BEEF  COWS 

By  T.  S.  HAMILTON,  Associate  in  Animal  Nutrition,  and  H.  P.  RUSK, 
Chief  of  Cattle  Husbandry 

Under  methods  of  harvesting  prevalent  thruout  much  of  the  corn 
belt  the  stalk,  leaves,  and  husks  of  the  corn  plant  are  left  in  the  fields. 
The  utilization  of  the  potential  feeding  value  of  this  by-product  has 
long  been  a  subject  for  study  and  experimentation.  Pasturing  in  the 
fields  is  obviously  wasteful  and  often  damages  the  soil  by  causing  it 
to  puddle.  Shredded  stover  and  ordinary  stover  from  shocked  corn  fail 
to  meet  the  requirements  fully,  because  large  portions  are  woody  and 
unpalatable,  and  consequently  are  wasted. 

The  production  of  normal  corn  silage  from  the  entire  corn  plant 
probably  makes  possible  the  most  complete  and  effective  utilization. 
However,  a  demand  for  a  method  which  does  not  limit  the  disposal  of 
the  grain  has  stimulated  a  revival  of  interest  in  the  possibilities  of 
silage  made  from  the  stover  without  the  grain.  Results  of  recent  ex- 
perimental feeding  trials  lend  some  encouragement  for  this  method  of 
utilizing  the  stover.  These  results,  together  with  the  fact  that  analyti- 
cal studies  indicate  that  so  far  as  the  chemical  constituents  are  con- 
cerned the  stover  contains  nearly  one-half  of  the  total  crude  protein, 
carbohydrates,  and  fat  of  the  entire  corn  plant,  have  led  to  many  ex- 
travagant claims  regarding  the  nutritive  value  of  stover  silage. 

The  nutritive  value  of  a  feed,  however,  depends  not  only  upon  its 
chemical  composition,  but  also  upon  the  ability  of  a  given  class  of  an- 
imals to  utilize  the  various  nutrients  in  the  combinations  found  in  that 
feed.  The  object  of  this  investigation,  therefore,  was  to  make  possible 
a  better  understanding  of  the  true  feeding  value  of  corn  stover  silage 
by  determining  not  only  the  apparent  digestibility  of  the  nutrients,  but 
also  the  metabolizable  energy  (energy  of  the  feed  consumed  minus  the 
energy  of  the  solid,  liquid,  and  gaseous  excreta)  of  this  product  when 
fed  to  beef  cows. 

PLAN  OF  INVESTIGATION 

The  investigation  was  carried  out  during  the  months  of  January 
and  February,  1923.  The  digestion  stalls  were  located  in  a  building 
which  was  kept  fairly  cool,  but  not  cold.  The  experimental  animals 
were  dry,  pregnant  cows  of  beef  type  weighing  about  1,200  pounds. 
These  cows  were  taken  from  a  group  that  was  being  wintered  on  a  ra- 
tion of  stover  silage  and  soybean  oil  meal,  and  consequently  were  ac- 
customed to  the  experimental  ration.  Eight  animals  were  used,  four 

467 


468  BULLETIN  No.  291  [May, 

in  each  of  two  15-day  digestion  trials.  Each  digestion  trial  consisted 
of  a  7-day  preliminary  feeding  period,  during  which  the  cows  were  fed 
individually  the  same  rations  which  they  were  to  receive  later  during 
the  collection  period,  and  a  period  in  the  digestion  stalls  of  8  days, 
during  the  last  7  days  of  which  the  collections  were  made. 

Collections  were  made  by  attendants  constantly  on  duty,  two  at 
a  time.  The  feces  were  collected  in  especially  constructed  shovels  and 
placed  immediately  in  air-tight  containers.  The  urine  was  collected  in 
galvanized  iron  buckets  made  to  fasten  on  the  ends  of  wooden  handles 
about  5  feet  long.  The  urine  was  poured  into  air-tight  containers 
immediately  after  collection.  In  order  to  guard  against  accidents  in 
making  the  collections,  a  large  shallow  water-tight  galvanized  iron  pan 
about  4  feet  long,  3  feet  wide,  and  6  inches  deep  was  placed  behind 
each  cow.  Each  stall  was  equipped  with  a  heavy  canvas  pad  about  3 
inches  thick  so  that  the  cow  did  not  stand  on  the  board  floor  of  the 
stall.  The  stalls  were  wide  enough  so  that  the  cows  could  lie  down  at 
will. 

The  ration  consisted  of  a  good  grade  of  corn  stover  silage,  soybean 
oil  meal,  salt,  and  water.  The  silage  used  during  both  trials  was  from 
the  same  silo,  altho  that  used  during  the  second  trial  was  taken  from 
a  lower  level.  The  silage  was  made  from  the  stover  of  shock  corn 
which  had  been  cut  and  shocked  at  the  usual  time.  After  the  ears  had 
dried  sufficiently  for  cribbing,  the  shocks  were  hauled  to  the  silo,  the 
ears  removed,  and  the  stover  cut  and  blown  into  the  silo,  water  being 
added  thru  the  distributor  at  the  rate  of  approximately  100  pounds  per 
100  pounds  of  stover.  The  same  shipment  of  soybean  oil  meal  served 
thruout  both  trials. 

Each  cow  was  fed  all  the  silage  she  would  eat.  During  the  diges- 
tion trials  this  averaged  nearly  50  pounds  of  fresh  silage  daily.1  The 
daily  allowance  of  soybean  oil  meal  was  1  pound  per  cow.  The  cows 
were  fed  twice  daily:  in  the  morning  (just  after  the  feces  and  urine  had 
been  aliquoted),  and  in  the  evening.  Half  the  daily  ration  was  given 
at  each  feeding.  The  soybean  oil  meal  was  sprinkled  over  the  silage. 
After  the  first  5  days  of  the  first  trial  1  ounce  of  salt  was  regularly 
added  to  the  morning  feed.  Water  was  offered  from  a  pail  twice  daily, 
once  before  the  morning  feed  and  again  before  the  evening  feed. 

METHOD  OF  SAMPLING 

The  urine  and  feces  were  aliquoted  daily,  about  8:30  o'clock  each 
morning.  Each  day's  excretion  of  urine  and  feces  from  each  cow  was 


'During  the  entire  winter  the  average  daily  consumption  of  the  lot  of  ten 
cows  from  which  the  group  was  taken  was  66.53  pounds  of  stover  silage  and  1 
pound  of  soybean  oil  meal. 


1927]  CORN  STOVER  SILAGE  FOR  BEEF  Cows  469 

separately  weighed,  mixed,  and  aliquoted.  The  aliquots  taken  thruout 
the  tests  were  one-tenth  the  daily  excretion.  The  urine  was  mixed  by 
shaking  and  stirring,  while  the  feces  were  mixed  and  quartered  down 
in  a  large  shallow  pan  with  the  aid  of  a  bricklayer's  hand  trowel.  The 
feces  were  of  such  consistency  that  this  method  of  mixing  proved  very 
satisfactory.  The  aliquoting  was  done  in  a  cool  room  and  as  quickly  as 
possible  so  that  the  loss  in  moisture  during  this  procedure  was  cer- 
tainly very  small.  The  daily  aliquots  from  each  animal  were  placed 
in  air-tight  containers  and  kept  at  about  freezing  temperature.  Each 
succeeding  daily  aliquot  was  added  to  the  preceding  one  until  the  end 
of  the  collection  period,  when  they  were  carefully  composited  and  an- 
alyzed. The  feces  were  analyzed  in  the  fresh  condition.  The  orts  re- 
maining in  the  manger  each  morning  were  weighed  and  immediately 
air-dried. 

The  silage  was  taken  from  the  silo  each  morning  and  brought  to 
the  digestion  room  in  large  canvas  bags  in  time  for  the  morning  feed- 
ing. It  was  then  mixed  and  the  daily  ration  was  weighed  out.  The 
evening  allowance  was  placed  in  50-pound  lard  cans  which  were  tightly 
covered.  While  the  silage  was  being  weighed  out  for  the  day's  feed,  an 
occasional  handful  was  placed  in  a  pail  for  analysis.  Exactly  1  kilo- 
gram of  silage  was  taken  in  this  manner  each  morning  for  analysis. 
This  sample  was  taken  immediately  to  the  laboratory  in  a  tightly  cov- 
ered pail  and  quickly  air-dried  at  about  65 °C.  The  daily  air-dried 
samples  were  combined  to  form  a  composite  sample  for  the  collection 
period.  The  orts  from  each  animal  were  treated  in  exactly  the  same 
manner.  Only  one  sample  of  soybean  oil  meal  was  analyzed,  and  this 
was  taken  by  placing  a  handful  of  the  meal  in  a  pail  each  morning  at 
the  time  the  feed  was  being  weighed  out. 


RESULTS  OF  EXPERIMENTS 

The  average  weight  of  the  four  cows  in  the  first  trial  was  1,255 
pounds  at  the  beginning  of  the  preliminary  period,  1,250  pounds  at  the 
beginning  of  the  collection  period,  1,194  pounds  at  the  end  of  the  trial, 
and  1,279  pounds  two  weeks  later;  thus,  the  average  loss  in  weight 
while  in  the  stalls  was  56  pounds  (Table  A,  Appendix) .  The  same  data 
for  the  four  cows  in  the  second  trial  are  1,141  pounds  at  the  start,  1,109 
when  placed  in  the  digestion  stalls,  and  1,084  at  the  end  of  the  trial, 
the  average  loss  in  weight  being  25  pounds.  One  week  after  their  re- 
turn to  the  feed  lot  these  cows  averaged  1,145  pounds  in  weight.  The 
nitrogen  balance  data  (Table  D  of  the  Appendix)  indicate  that  there 
was  some  loss  in  body  flesh,  tho,  because  of  the  immediate  return  of 
each  cow  to  her  original  weight  within  one  or  two  weeks  after  termi- 


470 


BULLETIN  No.  291 


nation  of  the  experiment,1  most  of  the  loss  in  weight  was  certainly  loss 
in  fill. 

The  percentage  composition  of  the  soybean  oil  meal  and  of  the 
corn  stover  silage  used  during  the  two  collection  periods  is  given  in 
Table  1.  The  silage  used  during  the  first  period  was  taken  from  the 


TABLE  1. — PERCENTAGE  COMPOSITION  AND  GROSS  ENERGY  OF  FEEDS 


Gross 

Feed 

Crude 

N-free 

Crude 

Ether 

Crude 

energy 

protein 

extract 

fiber 

extract 

ash 

per  100 

pounds 

therms 

Corn  stover  silage, 

Period  I  

28.41 

1.81 

14.13 

9.38 

.53 

2.56 

54.9 

Corn  stover  silage, 

Period  II  

25.03 

1.65 

12.65 

8.02 

.50 

2.21 

48.4 

Soybean  oil  meal  

90.63 

39.95 

36.18 

6.73 

5.07 

6.59 

197.8 

TABLE  2. — PERCENTAGE  COMPOSITION  AND  GROSS  ENERGY  OF  ORTS,  FECES, 

AND  URINE 


Cow 
No. 


Sample 


Dry 

sub- 
«tance 


Crude 
protein* 


N-free 
extract 


Crude 
fiber 


Ether 
extract 


Crude 
ash 


Gross 
energy 
per  100 
pounds 


Period  I 


1  

Orts  .... 

28.84 

1.25 

12.34 

9.41 

.39 

1.45 

therms 
50.5 

o1 

Feces  .  .  . 
Urine.  .  . 

16.35 

1.62 
(.73) 

7.14 

4.00 

.24 

3.35 

32.1 
8.3 

2  

Orts  
Feces  .  .  . 

26.61 
13.27 

1.67 
1.21 
(  74) 

13.40 
6.67 

9.10 
3.06 

.43 

.21 

2.01 
2.12 

52.3 
25.5 
6  8 

3  

Orts  
Feces.  .  . 

28.67 
13.82 

1.89 
1.44 

(  78) 

14.26 
5.94 

9.76 
3.16 

.51 
.23 

2.25 
3.05 

56.4 
28.3 
8.6 

4  

Orts  
Feces  .  .  . 
Urine.  .  . 

24.29 
15.38 

1.55 
1.40 

(.81) 

12.24 
6.66 

8.24 
3.78 

.39 

.29 

1.87 
3.25 

48.0 
29.9 
8.6 

Period  II 


5  

Orts  

34.36 

2.30 

18.04 

10.86 

.65 

2.51 

65.6 

Feces  .  .  . 
Urine  .  .  . 

14.76 

1.40 
(.60) 

7.46 

3.52 

.25 

2.13 

26.4 
7.6 

6  

Orts  
Feces  .  .  . 
Urine  .  .  . 

27.23 
12.92 

1.44 
1.23 

(.75) 

13.31 
6.28 

10.29 
3.17 

.35 

.28 

1.84 
1.96 

53.0 
23.0 
7.8 

7  

Orts  
Feces  .  .  . 

25.41 
15.43 

1.72 
1.35 
(  69) 

12.74 
7.64 

8.55 
3.71 

.47 
.36 

1.93 
2.37 

49.4 
28.8 
10.0 

8  

Orts  
Feces  .  .  . 
Urine  .  .  . 

35.09 
13.81 

1.80 
1.27 
(.74) 

16.55 
6.87 

14.22 
3.29 

.41 
.24 

2.11 
2.14 

69.2 
25.4 
7.6 

•In  case  of  urine  samples  the  figures  in  this  column  represent  the  percentage  of  total  nitrogen 
instead  of  crude  protein. 


*The  lot  of  ten  cows  from  which  these  eight  test  cows  were  taken  averaged 
1,055.5  pounds  when  started  on  this  ration,  November  1,  1922,  and  1,159  pounds  at 
the  end  of  the  winter  trial,  March  21,  1923.  The  average  total  gain  per  head  was 
103.5  pounds,  or  an  average  daily  gain  of  .742  pound,  for  the  139.5  days,  including 
time  spent  in  the  digestion  trials. 


CORN  STOVER  SILAGE  FOR  BEEF  Cows 


471 


upper  part  of  the  silo,  and  that  used  during  the  second  period  was 
taken  from  a  lower  level  in  the  silo. 

The  percentage  composition  of  the  orts,  the  fresh  feces,  and  the 
urine  is  given  in  Table  2.  In  addition  to  the  regular  routine  chemical 
determinations,  the  gross  energy  of  all  samples  was  regularly  deter- 
mined in  a  bomb  calorimeter. 


TABLE  3. — AMOUNTS  OF  FEED  OFFERED  AND  WATER  CONSUMED,  AND 
WEIGHT  OF  ORTS,  FECES,  AND  URINE 


Cow  No. 

Feed  offered 

Water 
consumed 

Orts 

Feces 

Urine 

Stover 
silage 

Soybean 
meal 

Salt 

Period  I 


1... 

Ibs. 
350 

Ibs. 

7 

oz. 
2 

Ibs. 
146.87 

/6s. 
4.04 

Ibs. 
261.49 

Ibs. 
107.27 

2  

320 

7 

2 

228.56 

24.32 

301.79 

132.78 

3  

300 

7 

2 

191.94 

53.98 

238.28 

82.15 

4  

320 

7 

2 

139.81 

19.55 

236.39 

102.83 

Period  II 


5... 

350 

7 

7 

172.87 

3.09 

285.99 

100.77 

6... 

350 

7 

7 

208  75 

4.42 

334.07 

97.42 

7 

350 

7 

7 

113.56 

25.03 

237.25 

100.90 

8..  ..  .. 

350 

7 

7 

172.25 

1.20 

289.97 

116.80 

The  total  weights  of  feed  offered,  water  consumed,  orts  left,  and 
feces  and  urine  excreted  during  the  two  7-day  collection  periods  are 
given  in  Table  3. 

DIGESTIBILITY  OF  CORN  STOVER  SILAGE 

All  the  data  relative  to  the  calculation  of  the  coefficients  of  diges- 
tibility of  the  nutrients  in  the  combined  ration  of  corn  stover  silage  and 
soybean  oil  meal,  when  fed  in  the  ratio  of  approximately  1  to  50,  are 
given  in  Table  4.  The  calculations  were  made  in  the  usual  manner  and 
the  table  is  self-explanatory. 

The  calculations  of  the  coefficients  of  digestibility  of  the  nutrients 
in  the  corn  stover  silage  alone  are  presented  in  Table  5.  The  correc- 
tion for  the  soybean  oil  meal  in  the  ration  was  made  in  the  usual  man- 
ner, using  coefficients  of  digestibility  for  soybean  oil  meal  obtained  at 
this  Station  on  sheep.1  The  nutrients  in  the  orts  are  assumed  to  be  de- 
rived entirely  from  the  corn  stover  silage.  Therefore  the  nutrients  con- 
sumed from  the  silage  are  calculated  by  subtracting  the  nutrients  in  the 
orts  from  the  corresponding  nutrients  in  the  silage  fed.  The  above  as- 
sumption is  made  because  of  the  small  quantity  of  soybean  oil  meal  in 
the  ration,  and  because  the  orts  remaining  in  the  manger  were  usually 

Unpublished  data  from  an  experiment  on  the  digestibility  of  soybean  pro- 
ducts with  sheep  at  the  University  of  Illinois. 


472 


BULLETIN  No.  291 


[May, 


TABLE  4A. — DIGESTIBILITY  OF  THE  COMBINED  RATION  OP  CORN  STOVER  SILAGE 

AND  SOYBEAN  OIL  MEAL:  PERIOD  I 

(Amounts  in  pounds) 


Dry 

substance 

Crude 
protein 

N-free 

extract 

Crude 
fiber 

Ether 
extract 

Cow  No.  1 
Silage  fed,  350  pounds  

99.4 

6.3 

49.4 

32.8 

1.8 

Soybean  oil  meal  fed,  7  pounds  

6.3 

2.8 

2.5 

.5 

.4 

Total  ration  

105.7 

9.1 

51.9 

33.3 

2.2 

Orts,  4.04  pounds  

1.0 

.1 

.5 

.4 

.0 

104.7 

9.0 

51.4 

32  9 

2  2 

Feces,  261.49  pounds  

42.7 

4.2 

18.7 

10.5 

.6 

Nutrients  digested  

62.0 

4.8 

32.7 

22  4 

1.5 

Percentage  digested  

(59.2) 

(53.3) 

(63.6) 

(68.1) 

(68.2) 

Cow  No.  2 
Silage  fed,  320.0  pounds    

90.9 

5.8 

45.2 

30  0 

1  7 

Soybean  oil  meal  fed,  7  pounds  

6.3 

2.8 

2.5 

.5 

.4 

Total  ration  

97.2 

8  6 

47.7 

30  5 

2.1 

Orts,  24.32  pounds  

6.5 

.4 

3.3 

2.2 

.1 

Nutrients  consumed  

90.7 

8.2 

44.4 

28  3 

2.0 

Feces,  301.79  pounds  

40.0 

3.6 

20.1 

9.2 

.6 

Nutrients  digested  

50.7 

4.6 

24.3 

19   1 

1.4 

(55  9) 

(56  1) 

(54.7) 

(67  5) 

(70  0) 

Cow  No.  3 
Silage  fed  300  pounds 

85  2 

5  4 

42  4 

28  1 

1  6 

Soybean  oil  meal  fed,  7  pounds  

6.3 

2.8 

2.5 

.5 

.4 

Total  ration  

91.5 

8.2 

44.9 

28  6 

2.0 

Orts,  53.98  pounds  

15.5 

1.0 

7.7 

5.3 

.3 

Nutrients  consumed  

76.0 

7.2 

37.2 

23  3 

1.7 

Feces,  238.28  pounds  

32.9 

3.4 

14.2 

7.5 

.6 

Nutrients  digested  

43.1 

3.8 

23.0 

15.8 

1.1 

Percentage  digested  

(56.7) 

(52.8) 

(61.8) 

(67.8) 

(64.7) 

Cow  No.  4 
Silage  fed,  320  pounds  

90  9 

5.8 

45  2 

30  0 

1.7 

Soybean  oil  meal  fed,  7  pounds  

6.3 

2.8 

2.5 

.5 

.4 

Total  ration  

97.2 

8.6 

47.7 

30.5 

2.1 

Orts,  19.55  pounds  

4.7 

.3 

2.4 

1.6 

.1 

Nutrients  consumed  

92.5 

8.3 

45.3 

28.9 

2.0 

Feces,  236.39  pounds  

36.4 

3.3 

15.7 

8.9 

.7 

Nutrients  digested  

56   1 

5  0 

29  6 

20  0 

1.3 

Percentage  digested  

(60.6) 

(60.2) 

(65.4) 

(69.2) 

(65.0) 

the  larger,  most  unpalatable  pieces  of  the  stalk  with  no  visible  quan- 
tity of  oil  meal.  The  coefficients  of  digestibility  of  the  soybean  oil 
meal,  taken  from  the  average  figures  obtained  on  twelve  sheep,  are  as 
follows:  dry  substance,  98  percent;  crude  protein,  88  percent;  N-free 
extract,  100  percent;  ether  extract,  95  percent;  and  crude  fiber,  60  per- 
cent. 

A  summary  of  the  coefficients  of  digestibility  of  the  nutrients  in 
the  combined  ration  calculated  in  Table  4  is  given  in  Table  6,  while 
Table  7  gives  the  summary  of  the  coefficients  of  digestibility  of  the 
corn  stover  silage  alone  as  calculated  in  Table  5. 

A  noticeable  effect  of  the  correction  for  the  soybean  oil  meal  is  in 
the  lowering. of  the  apparent  digestibility  of  the  crude  protein  of  the 
combined  rations  from  an  average  percentage  of  55.6  to  39.  Also,  the 
digestibility  of  the  ether  extract  was  lowered  from  an  average  of  65.7 
percent  for  the  combined  ration  to  an  average  of  59.2  percent  for  the 
silage  alone.  The  total  amount  of  ether  extract  in  the  silage,  how- 


1927] 


CORN  STOVER  SILAGE  FOR  BEEF  Cows 


473 


TABLE  4B. — DIGESTIBILITY  OF  THE  COMBINED  RATION  OF  CORN  STOVER  SILAGE 

AND  SOYBEAN  OIL  MEAL:  PERIOD  II 

(Amounts  in  pounds) 


Dry 
substance 

Crude 
protein 

N-free 
extract 

Crude 
fiber 

Ether 
extract 

Cow  No.  6 
Silage  fed,  350  pounds  

87  6 

5.8 

44.3 

28.1 

1.8 

Soybean  oil  meal  fed,  7  pounds  

6.3 

2.8 

2.5 

.5 

.4 

93  9 

8  6 

46  8 

28  6 

2  2 

Orts,  3.09  pounds  

1.1 

.1 

.5 

.3 

.0 

Nutrients  consumed  

92  8 

8  5 

46  3 

28  3 

2.2 

Feces,  285.99  pounds  

42.2 

4.0 

21.3 

10.1 

.7 

Nutrients  digested  

50  6 

4.5 

25.0 

18.2 

1.5 

Percentage  digested  

(54.5) 

(52.9) 

(54.0) 

(64.3) 

(68.2) 

Cow  No.  6 
Silage  fed,  350  pounds   

87  6 

5  8 

44.3 

28.1 

1.8 

Soybean  oil  meal  fed,  7  pounds  

6.3 

2.8 

2.5 

.5 

.4 

Total  ration  

93  9 

8.6 

46.8 

28.6 

2.2 

Orts,  4.42  pounds  

1.2 

.1 

.6 

.4 

.0 

Nutrients  consumed  

92.7 

8.5 

46.2 

28.2 

2.2 

Feces,  334.07  pounds  

43.2 

4.1 

21.0 

10.6 

.9 

49  5 

4  4 

25  2 

17.6 

1.3 

(53  4) 

(51.8) 

(54.5) 

(62.4) 

(59.1) 

Cow  No.  7 
Silage  fed,  350  pounds  

87.6 

5.8 

44.3 

28.1 

1.8 

Soybean  oil  meal  fed,  7  pounds  

6.3 

2.8 

2.5 

.5 

.4 

Total  ration  

93.9 

8.6 

46.8 

28.6 

2.2 

Orts,  25.03  pounds  

6.4 

.4 

3.2 

2.1 

.1 

87.5 

8.2 

43.6 

26.5 

2.1 

Feces,  237.25  pounds  

36.6 

3.2 

18.1 

8.8 

.8 

50.9 

5.0 

25.5 

17.7 

1.3 

Percentage  digested  

(58.2) 

(61.0) 

(58.5") 

(66.8) 

(61.9) 

Cow  No.  8 
Silage  fed,  350  pounds  

87.6 

5.8 

44.3 

28.1 

1.8 

Soybean  oil  meal  fed,  7  pounds  

2.8 

2.5 

.5 

.4 

Total  ration  

93.9 

~O 

46.8 

28.6 

2.2 

Orts,  1.20  pounds  

.4 

.0 

.2 

.2 

.0 

Nutrients  consumed  
Feces,  289.97  pounds  

93.5 
40.0 

8.6 
3.7 

46.6 
19.9 

28.4 
9.4 

2.2 

.7 

Nutrients  digested  

53.5 

4.9 

26.7 

18.9 

1.5 

Percentage  digested  

(57.2) 

(57.0) 

(57.2) 

(66.5) 

(68.2) 

ever,  is  so  small  in  comparison  with  the  other  nutrients  that  this  ap- 
parent decrease  in  digestibility  of  ether  extract  need  not  be  considered. 
The  other  nutrients  are  little  affected. 

The  average  percentages  of  digestible  nutrients  in  the  corn  stover 
silage  are  tabulated  in  Table  8. 

PREVIOUS  INVESTIGATIONS  INDICATE  BETTER  UTILIZATION 
OF  CORN  ROUGHAGES  BY  CATTLE  THAN  BY  SHEEP 

The  digestibility  of  corn  stover  silage  has  been  determined  by 
Tangl  and  Weiser.1  Using  wethers  as  experimental  animals,  these  in- 
vestigators determined,  in  duplicate,  the  digestibility  of  stover  silage 
taken  at  three  different  levels  from  a  reinforced  concrete,  silo.  A  com- 
parison of  the  average  digestion  coefficients  obtained  by  Tangl  and 
Weiser,  and  those  obtained  in  this  investigation,  is  given  in  Table  9. 
This  comparison  shows  a  fairly  close  agreement  between  the  values 
obtained  in  the  two  investigations,  in  all  the  nutrients  except  crude 


474  BULLETIN  No.  291  [May, 

TABLE  5. — CALCULATION  OF  DIGESTIBILITY  OF  CORN  STOVER  SILAGE 
(Amounts  in  pounds) 


Dry 

substance 

Crude 
protein 

N-free 
extract 

Crude 
fiber 

Ether 
extract 

Period  I 


Cow  No.  1. 

98.4 

6  3 

48  9 

32  4 

1  8 

Nutrients  digested 
Total  

62.0 

4.8 

32.7 

22.4 

1.5 

6.2 

2.5 

2  5 

3 

.3 

Silage  

55.8 

2.3 

30.2 

22  1 

1.2 

Coefficient  of  digestibility  for  silage  .... 

Cow  No.  2 

(57) 
84.4 

(37) 
5  4 

(62) 
41.9 

(68) 
27  8 

(67) 
1.6 

Nutrients  digested 
Total  

50.7 

4.6 

24.3 

19.1 

1.3 

6.2 

2.5 

2  5 

3 

.3 

Silage  

44.5 

2.1 

21.8 

18  8 

1.0 

Coefficient  of  digestibility  for  silage  .... 
Cow  No.  3 
Nutrients  consumed,  silage  

(53) 
69.7 

(39) 
4  4 

(52) 
34  7 

(68) 
22  8 

(63) 
1.3 

Nutrients  digested 
Total         

43  1 

3  8 

23  0 

15  8 

1   1 

Soybean  oil  meal  

6  2 

2  5 

2  5 

3 

.3 

Silage  

36.9 

1.3 

20.5 

15.5 

.8 

Coefficient  of  digestibility  for  silage  .... 
Cow  No.  4 
Nutrients  consumed,  silage  

(53) 
86  2 

(30) 
5  5 

(59) 
42  8 

(68) 
28  4 

(61) 
1.6 

Nutrients  digested 
Total  

56.1 

5.0 

29.6 

20.0 

1.3 

Soybean  oil  meal  

6.2 

2.5 

2.5 

.3 

.3 

Silage  

49.9 

2.5 

27  1 

19  7 

1.0 

Coefficient  of  digestibility  for  silage.  .  .  . 

(58) 

(45) 

(63) 

(69) 

(63) 

Period  II 


Cow  No.  5 
Nutrients  consumed,  silage  

86  5 

5  7 

43.8 

27  8 

1  7 

Nutrients  digested 
Total  

50  6 

4  5 

25  0 

18  2 

1  4 

Soybean  oil  meal  

6.2 

2  5 

2.5 

3 

.3 

Silage  

44  4 

2  0 

22  5 

17  9 

1  i 

Coefficient  of  digestibility  for  silage  .... 
Cow  No.  6 
Nutrients  consumed,  silage  

(51) 
86.4 

(35) 
5  7 

(51) 
43.7 

(64) 
27.7 

(65) 
1  7 

Nutrients  digested 
Total  

49  5 

4  4 

25.2 

17.6 

1  1 

Soybean  oil  meal  

6.2 

2.5 

2.5 

.3 

.3 

Silage  

43  3 

1  9 

22  7 

17  3 

8 

Coefficient  of  digestibility  for  silage  .... 
Cow  No.  7 
Nutrients  consumed,  silage  

(50) 
81.2 

(33) 
5  4 

(52) 
41.1 

(62) 
26  0 

(47) 
1.6 

Nutrients  digested 
Total  

50.9 

5  0 

25.5 

17.7 

1.1 

Soybean  oil  meal  

6.2 

2.5 

2.5 

.3 

.3 

Silage  

44  7 

2  5 

23  0 

17  4 

.8 

Coefficient  of  digestibility  for  silage  .... 
Cow  No.  8 
Nutrients  consumed,  silage  

(55) 
87.2 

(46) 
5.8 

(56) 
44.1 

(67) 
27.9 

(50) 
1.8 

Nutrients  digested 
Total  

53.5 

4.9 

26.7 

18.9 

1.4 

Soybean  oil  meal  

6.2 

2.5 

2  5 

3 

.3 

Silage  

47.3 

2.4 

24.2 

18.6 

1.1 

Coefficient  of  digestibility  for  silage  .... 

(54) 

(41) 

(55) 

(67) 

(61) 

fiber  and  crude  fat.  The  digestibility  of  the  crude  fiber  of  corn  stover 
silage  obtained  by  Hamilton  and  Rusk  on  cattle  was  66.7  percent,  as 
compared  with  57.8  percent  obtained  by  Tangl  and  Weiser  on  sheep. 
It  is  a  noticeable  fact  that  the  differences  in  the  coefficients  obtained 
in  the  two  investigations  are  all  in  favor  of  the  cattle,  except  the  co- 


1987] 


CORN  STOVER  SILAGE  FOR  BEEF  Cows 


475 


TABLE  6. — SUMMARY  OF  COEFFICIENTS  OF  DIGESTIBILITY  OF  THE  COMBINED  RATION 
OF  CORN  STOVER  SILAGE  AND  SOYBEAN  OIL  MEAL 


Cow  No. 

Dry 

substance 

Crude 
protein 

N-free 
extract 

Crude 
fiber 

Ether 
extract 

Period  I 


I.. 

59 

53 

64 

68 

68 

2  

56 

56 

55 

68 

70 

3  

57 

53 

62 

68 

65 

4  

61 

60 

65 

69 

65 

Average  

58.2 

55.5 

61.5 

68.3 

67.0 

Period  II 


5  

55 

53 

54 

64 

68 

6  

53 

52 

55 

62 

59 

7  

58 

61 

59 

67 

62 

8  

57 

57 

57 

67 

68 

Average  

55.8 

55.8 

56.3 

65 

64.3 

Averaare  for  Periods  I 
and  II  

57.0 

55.6 

58.9 

66.6 

65.7 

efficients  for  crude  fat,  which  have  little  significance  because  of  the 
small  amount  of  ether  extract  in  corn  stover  silage. 

The  question  whether  or  not  different  genera  of  ruminants  digest 
roughages  with  the  same  efficiency  has  not  been  satisfactorily  an- 
swered. Investigations  comparing  the  digestive  powers  of  cattle  and 
sheep  for  the  same  feed  are  not  numerous,  and  the  evidence  obtained  in 
the  majority  of  these  is  unsatisfactory  in  view  of  the  use  of  only  one 
or  two  animals.  A  cursory  glance  at  the  results  of  almost  any  diges- 
tion trial  in  which  two. or  more  animals  are  used  will  show  that  con- 
siderable differences  in  digestion  coefficients  occur  between  individual 
animals  of  the  same  kind. 

Bartlett2  has  carried  out  a  series  of  digestion  experiments  with 
sheep  and  steers  in  which  he  compared  the  digestibility  of  seventeen 
different  rations  by  sheep  and  by  steers.  Of  the  seventeen  rations, 
eight  were  roughages  or  largely  roughages  and  the  remainder  were  con- 
centrates or  largely  concentrates.  The  average  coefficients  of  digestibil- 
ity for  the  dry  substance,  crude  protein,  and  crude  fiber  of  the  eight 
roughages  were  determined  to  be  as  follows: 


By  steers  By  sheep 

Dry  substance 61.6  58.3 

Crude  protein 49 . 5  50 . 3 

Crude  fiber..  .  61.2  55.1 


Difference  in 
favor  of  steers 

+  3.3 

o 


Bartlett  concluded  that  the  steers  used  in  his  experiments  "had  a 
greater  capacity  for  digesting  coarse  fodders  low  in  protein,  like  tim- 
othy hay  and  corn  fodders,  than  sheep,"  and  the  above  figures,  espe- 
cially, indicate  that  this  is  true.  He  further  states:  "It  is  evident  from 


476 


BULLETIN  No.  291 


[May, 


TABLE  7. — SUMMARY  OF  COEFFICIENTS  OF  DIGESTIBILITY  OF  CORN  STOVER  SILAGE 


Cow  No. 

Dry 

substance 

Crude 
protein 

N-free 
extract 

Crude 
fiber 

Ether 
extract 

Period  I 


1.. 

57 

37 

62 

68 

67 

2  

53 

39 

52 

68 

63 

3  

53 

30 

59 

68 

61 

4  

58 

45 

63 

69 

63 

Average  

55.3 

37.8 

59.0 

68.3 

63.5 

Period  II 


5  

51 

35 

51 

64 

65 

6  

50 

33 

52 

62 

47 

7  

55 

46 

56 

67 

50 

8  

54 

41 

55 

67 

61 

Average  

52.5 

38.5 

53.5 

65.0 

55.8 

Average  for  Periods  I 
and  II  

53.9 

38.2 

56.3 

66.7 

59.2 

Coefficients  of  digesti- 
bility  for   combined 
ration  

57.0 

55.6 

58.9 

66.6 

65.7 

TABLE  8. — PERCENTAGES  OF  DIGESTIBLE  NUTRIENTS  IN  CORN  STOVER  SILAGE 


Dry 

substance 

Crude 
protein 

N-free 
extract 

Crude 
fiber 

Ether 
extract 

Period  I  

15.7 

.68 

8.3 

6.4 

.34 

Period  II  

13.2 

.64 

6.7 

5.2 

.28 

Average*  

14.5 

.66 

7.6 

5.8 

.31 

"The  average  percentage  of  dry  substance  in  the  two  samples  of  silage  used  was 
26.72. 

TABLE  9. — COMPARISON  OF  COEFFICIENTS  OF  DIGESTIBILITY  OF  CORN  STOVER  SILAGE 
OBTAINED  BY  DIFFERENT  INVESTIGATORS 


Hamilton 
and  Rusk 
(with  cattle) 

Tangl  and 
Weiser 
(with  sheep) 

Difference 
in  favor 
of  cattle 

Dry  substance  

53.9 

51.2 

2.7 

Crude  protein  

38.2 

32.9 

5.6 

N-free  extract  

56.3 

56.2 

.1 

Crude  fiber  

66.7 

57.8 

8.9 

Crude  fat  

59.2 

68.1 

—8.9 

a  study  of  these  results  and  others  before  published  that  as  great  dif- 
ferences in  digestion  coefficients  will  occur  between  sheep,  individually, 
as  is  likely  to  occur  between  sheep  and  steers." 

Jordan  and  Hall3  made  a  compilation  of  the  results  of  American 
digestion  experiments  up  to  1898,  and  concluded  that  "American  ex- 
periments neither  confirm  nor  disprove  the  general  assumption  of  Ger- 


1927] 


CORN  STOVER  SILAGE  FOR  BEEF  Cows 


477 


man  experimenters  that  the  different  genera  of  ruminants  digest  coarse 
fodders  with  practically  the  same  efficiency." 

In  discussing  this  question  Armsby4  states:  ".  .  .  .  it  would  ap- 
pear that  in  the  case  of  the  coarser  and  less  digestible  forms  of  forage 
a  distinct  difference  exists  in  favor  of  cattle."  The  evidence,  showing 
a  greater  utilization  of  the  nutrients,  especially  the  crude  fiber,  of  the 
coarser  roughages  by  cattle,  is  much  more  consistent  for  the  rough- 
ages derived  from  the  corn  plant  than  for  the  hays. 

In  Table  10  are  given  the  results  of  experiments  as  reported  by 
several  investigators  comparing  the  digestibility  of  the  same  kind  of 


TABLE  10. — COMPARISON  OF  DIGESTIBILITY  OF  THE  SAME  KINDS  OF  FEED  BY 
STEERS  AND  BY  SHEEP 


Coefficients  of  digestibility 

Investi- 
gator and 
reference 

Dry 

substance 

Crude 
protein 

N-free 
extract 

Crude 
fiber 

Ether 
extract 

Corn  silage 
1  steer  

68.1 
53.8 
14.3 

75.6 
66.4 
9.2 

63.1 
60.0 
3.1 

72.9 
64.9 
8.0 

67.4 
62.5 
4.9 

44.0 
21.5 
22.5 

65.0 
56.0 
9.0 

46.7 
50.9 
—4.2 

56.9 
46.7 
10.2 

58.6 
55.8 
2.8 

69.7 
54.9 
14.8 

75.3 

68.6 
~6.7 

64.1 
65.0 
—  .9 

74.4 
68.2 
6.2 

66.8 
61.6 
5.2 

77.6 
63.6 
14.0 

81.9 
70.6 
11.3 

67.2 
57.8 
9.4 

79.8 
69.9 
9.9 

74.4 
68.1 
6.3 

76.6 
68.3 
8.3 

89.5 
88.5 
1.0 

68.3 
75.5 
—7.2 

72.3 
59.3 
13.0 

79.2 
77.8 
1.4 

Frear' 
Armsby8 
Bartlett1 
Bartlett1 
Armsby' 

2  sheep  

Diff.  in  favor  of  steers.  .  . 
Corn  silage 
3  steers  

2  sheep  

Diff.  in  favor  of  steers  .  .  . 
Learning  corn  silage 

2  sheep  

Diff.  in  favor  of  steers.  .  . 
Corn  fodder  (Sanford  corn) 

2  sheep  

Diff.  in  favor  of  steers.  .  . 
Corn  fodder 
2  steers  

1  sheep  

Diff.  in  favor  of  steers  .  .  . 

roughage  from  the  corn  plant  by  cattle  and  by  sheep.  It  is  to  be  re- 
gretted that  a  larger  number  of  animals  was  not  used  in  these  compara- 
tive experiments. 

These  direct  comparisons  and  the  less  direct  comparison  made  in 
Table  9  all  indicate  consistently  better  utilization  by  cattle  than  by 
sheep  of  the  nutrients  from  the  roughages  derived  from  the  corn  plant. 
While  the  evidence  is  not  sufficient  to  warrant  a  definite  conclusion,  it 
is  quite  probable  that  cattle  do  digest  roughages  from  the  corn  plant 
better  than  do  sheep.  If  this  is  true,  it  is  also  reasonable  to  suppose 
that  the  same  is  true  of  all  coarse  roughages  low  in  protein,  altho  the 
available  evidence  on  this  point  is  less  conclusive. 

In  their  investigation  Tangl  and  Weiser  also  determined  the  di- 
gestibility of  ordinary  dry  corn  stover  (averaging  85.0  percent  dry 
substance)  with  sheep.  A  comparison  of  the  coefficients  of  digestibility 
of  corn  stover  and  corn  stover  silage  is  made  by  these  authors,  and  a 


478 


BULLETIN  No.  291 


[May, 


table  given  by  them  is  copied  in  slightly  different  form  in  Table  11 
of  this  bulletin.  These  data  show  no  difference  in  the  digestibility  of 
dry  substance,  a  difference  in  favor  of  the  dry  corn  stover  of  3.4  per- 
cent in  the  digestibility  of  the  crude  protein,  and  of  2.8  percent  in  that 
of  the  nitrogen-free  extract,  and  a  difference  in  favor  of  the  silage  of 

TABLE  11. — COMPARISON  OF  COEFFICIENTS  OF  DIGESTIBILITY  OF  CORN  STOVER  AND 

CORN  STOVER  SILAGE* 


Digestibility  of  — 

Difference  in  favor  of  — 

Corn  stover 
silage 

Corn 
stover 

Corn 
stover 

Corn  stover 
silage 

Dry  substance  

51.2 
32.9 
56.2 

57.8 
68.1 

51.2 
36.3 
59.0 
53.5 
58.3 

0 
3.4 

2.8 

0 

4.3 

9.8 

Crude  protein  

N-free  extract  

Crude  fiber  

Crude  fat  

'From  Tangl  and  Weiser  (loc.  tit.). 

4.3  percent  for  crude  fiber,  and  9.8  percent  for  crude  fat.  These  differ- 
ences are  small,  and  when  the  total  dry  substance  consumed  from  both 
feeds  is  found  to  have  averaged  only  520  grams  of  corn  stover  daily 
per  head,  and  the  corn  stover  silage  528  grams,  the  differences  are  in- 
significant. 


TABLE  12. — PERCENTAGE  COMPOSITION  AND  PERCENTAGE  OF  DIGESTIBLE  NUTRIENTS 
IN  WHOLE  CORN  SILAGE,  CORN  STOVER,  AND  CORN  STOVER  SILAGE 


Composition 


Fresh 

Dry  matter  in  — 

Whole 
corn 
silage* 

Corn 
stover 
silageb 

Corn 
stover0 
(field) 

Whole 
corn 
silage* 

Corn 
stover 
silageb 

Corn 
stover0 
(field) 

Dry  substance  

20.0 
1.7 
11.1 
5.4 
.7 
1.1 

26.7 
1.7 
13.4 
8.7 
.5 
2.4 

60.0 
4.6 
30.1 
20.6 
.8 
3.9 

100 
8.5 
55.5 
27.0 
3.5 
5.5 

100 
6.4 
50.1 
32.6 
1.9 
9.0 

100 
7.7 
50.2 
34.3 
1.3 
6.5 

Crude  protein  

N-free  extract  

Crude  fiber  

Crude  fat  

Crude  ash  

Digestible  nutrients 

Crude  protein  

.9 
7.7 
3.5 
.5 

.7 
7.6 
5.8 
.3 

1.7 
17.8 
13.2 
.6 

4.5 
38.5 
17.5 
2.5 

2.6 

28.4 
21.7 
1.4 

2.8 
29.7 
22.0 
.9 

N-free  extract  

Crude  fiber  

Crude  fat  

"Lindsey,  Haskins,  Smith,  and  Beals  (loc.  tit.),  average  of  50  analyses. 

bHamilton  and  Rusk. 

°Lindsey,  Haskins,  Smith,  and  Beals  (loc.  tit.),  average  of  47  analyses. 


CORN  STOVER  SILAGE  FOR  BEEF  Cows  479 

The  composition  and  percentage  of  digestible  nutrients  of  whole 
corn  silage,  corn  stover,  and  corn  stover  silage  are  given  in  Table  12. 
The  data  concerning  the  whole  corn  silage  and  corn  stover  are  taken 
from  the  compilation  by  Lindsey,  Haskins,  Smith,  and  Beals,7  and  that 
for  the  corn  stover  silage  from  the  present  investigation. 

STOVER  SILAGE  ABOUT  TWO-THIRDS  AS  VALUABLE  AS 

WHOLE  CORN  SILAGE 

It  is  evident  from  the  data  in  Table  12  that  there  is  no  great 
change  in  chemical  composition  brought  about  by  ensiling  corn  stover, 
and  further  that  the  availability  of  the  nutrients  to  ruminants  is  prac- 
tically the  same.  The  increased  palatability  of  the  silage,  the  conse- 
quent smaller  waste  in  feeding,  and  the  fact  that  there  is  no  loss  of 
material  from  exposure  to  rain  and  wind,  insure  a  much  greater  ulti- 
mate utilization  of  the  nutrients  of  the  corn  crop  when  the  stover  is 
put  in  the  silo  than  when  it  is  left  in  the  field.  A  comparison  of  the 
nutrients  available  in  the  stover  silage  with  those  in  the  whole  corn 
silage  shows  about  85  percent  as  much  total  digestible  nutrients  in  the 
stover  silage  as  in  the  same  weight  of  whole  corn  silage.  However,  ex- 
tensive feeding  trials  at  this  Station  indicate  that  in  practical  feeding 
stover  silage  is  only  about  two-thirds  as  valuable  as  normal  silage, 
pound  for  pound  on  fresh  basis. 

METABOLIZABLE  ENERGY  OF  CORN  STOVER  SILAGE 
In  addition  to  the  regular  routine  analyses,  the  gross  energy  of 
the  feed,  orts,  feces,  and  urine  was  determined  by  means  of  a  calori- 
metric  bomb.  The  metabolizable  energy  was  computed  by  deducting 
from  the  gross  energy  of  the  feed  consumed  the  energy  of  the  feces, 
urine,  and  methane. 

The  simple  digestion  apparatus  used  for  these  experiments  was  not 
provided  with  means  for  measuring  the  methane  produced,  so  the  en- 
ergy loss  due  to  this  gas  had  to  be  calculated.  Armsby  has  shown  that 
an  average  of  4.5  grams  of  methane  are  produced  for  every  100  grams 
of  carbohydrates  digested  by  a  ruminant.8  For  the  heat  of  combustion 
of  methane  Armsby9  uses  the  figure  13.344  large  calories  per  gram. 
Thus  to  calculate  the  energy  loss  due  to  gaseous  fermentation  for  an 
animal  during  a  collection  period,  the  sum  of  the  weights  in  grams  of 
the  nitrogen-free  extract  and  crude  fiber  digested  during  the  period, 
divided  by  100  and  multiplied  by  4.5,  gives  the  weight  in  grams  of 
methane  produced.  The  weight  in  grams  of  methane  produced  multi- 
plied by  13.34  gives  the  energy  content  of  the  methane  in  calories. 
This  represents  a  loss  of  energy  to  the  animal,  and  is  deducted  from  the 
energy  of  the  feed. 

Table  B  of  the  Appendix  gives,  for  each  cow,  the  total  dry  sub- 
stance, total  nitrogen,  and  gross  energy  of  the  feed  consumed,  and  of 


480  BULLETIN  No.  291  [May, 

the  feces  excreted;  the  total  digestible  carbohydrates,  their  methane 
equivalent  in  grams  and  in  therms  of  energy;  the  total  digestible  or- 
ganic nutrients;  and  the  nitrogen  and  energy  of  the  urine. 

An  accurate  computation  of  the  metabolizable  energy  of  a  feed  or 
ration  must  involve  a  correction  for  the  nitrogen  gained  or  lost  by  the 
animal.  If  the  animal  is  losing  nitrogen  during  the  period,  it  must  be 
recognized  that  part  of  the  energy  of  the  urine  has  originated  from 
partially  oxidized  body  protein.  According  to  Rubner10  the  potential 
energy  of  the  urine  is  increased  by  about  7.45  calories  for  each  gram 
of  urinary  nitrogen  coming  from  the  oxidation  of  body  protein.  There- 
fore, in  case  of  a  negative  nitrogen  balance,  indicating  that  body  pro- 
tein is  being  broken  down,  for  each  gram  of  nitrogen  in  the  urine  above 
that  derived  from  the  feed,  equal  to  the  negative  nitrogen  balance, 
7.45  calories  must  be  subtracted  from  the  gross  energy  of  the  urine. 
On  the  other  hand,  when  nitrogen  is  being  stored  in  the  body,  as  indi- 
cated by  a  positive  nitrogen  balance,  7.45  calories  must  be  added  to 
the  gross  energy  of  the  urine  for  each  gram  of  nitrogen  stored,  since 
this  amount  of  metabolizable  energy  is  being  retained  in  the  body. 
For  example,  Cow  No.  1  had  a  negative  nitrogen  balance  of  50  grams 
for  the  whole  period.  Therefore  50  times  7.45  calories,  or  372.5  cal- 
ories must  be  subtracted  from  the  gross  energy  of  the  urine  to  give  the 
metabolizable  energy  due  to  the  feed  alone.  Cow  No.  5  showed  a  pos- 
itive balance  of  53  grams  of  nitrogen,  so  that  394.9  calories  are  added 
to  the  gross  energy  of  the  urine. 

Table  D  of  the  Appendix  gives  the  nitrogen  balances  of  the  cows. 
Table  E  shows  the  calculation  of  the  metabolizable  energy. 

The  metabolizable  energy  calculated  as  described  above,  of  course 
gives  the  metabolizable  energy  for  the  ration  as  fed,  which  included 
one  pound  of  soybean  oil  meal.  In  order  to  correct  for  this  small  quan- 
tity of  concentrate,  and  to  secure  the  metabolizable  energy  derived 
from  the  corn  stover  silage  alone,  figures  suggested  by  Professor 
Armsby  are  again  used.  According  to  Armsby11  the  metabolizable 
energy  per  pound  of  digestible  organic  matter  in  oil  meals  and  concen- 
trates high  in  protein  is  between  1.996  and  2.177  therms  for  ruminants. 
The  average  of  these  two  figures  is  2.087  therms.  The  total  digestible 
organic  matter  furnished  by  the  soybean  oil  meal  was  5.63  pounds  to 
each  cow:  5.63  multiplied  by  2.087  gives  11.75  therms  of  metabolizable 
energy  obtained  from  the  ingestion  of  the  soybean  oil  meal.  Therefore, 
subtracting  11.75  therms  from  the  total  metabolizable  energy  in  the 
combined  ration  for  each  cow  gives  the  metabolizable  energy  derived 
from  the  corn  stover  silage  alone. 

The  metabolizable  energy  of  the  combined  ration  and  of  the  corn 
stover  silage  alone  is  given  in  Table  13. 

The  average  metabolizable  energy  for  corn  stover  silage  alone  is 
1.57  therms  per  pound  of  digestible  organic  matter  in  the  silage  (Table 


1927] 


CORN  STOVER  SILAGE  FOR  BEEF  Cows 


481 


TABLE  13. — METABOLIZABLE  ENERGY:  SUMMARY 
(Therms) 


Metabolizable  energy  of 
combined  ration 

Metabolizable  energy  of  corn 
stover  silage  alone 

Cow 
No. 

Total 

Per 
kilogram 
dry 
substance 
consumed 

Per 
pound 
digestible 
organic 
matter 

Total 

Per 
kilogram 
dry 
substance 
consumed 

Per 
pound 
digestible 
organic 
matter 

Period  I 


1.. 

96.5 
79.9 
63.1 

87.2 

2.03 
1.94 
1.83 
2.08 
1.97 

1.57 
1.62 
1.44 
1.56 
1.55 

84.75 
68.15 
51.35 
75.45 

1.90 
1.78 
1.62 
1.93 
1.81 

1.52 
1.56 
1.35 
1.50 
1.48 

2  

3  

4  

Average  .  . 

Period  II 

5  

85.8 
85.0 
80.3 

87.8 

2.04 
2.02 
2.02 
2.07 
2.04 

1.75 
1.76 
1.63 
1.69 
1.71 

74.05 
73.25 
68.55 
76.05 

1.88 
1.87 
1.86 
1.92 

1.88 

1.70 
1.71 
1.57 
1.64 
1.66 

6  

7  

8  

Average  .  . 

Average  for  Periods 
I  and  II  .  . 

2.00 

1.63 

1.85 

1.57 

13).  Armsby11  gives  the  figure  1.588  therms  of  metabolizable  energy 
per  pound  of  digestible  organic  matter  obtained  from  roughages  in 
general  by  ruminants. 

SUMMARY 

The  average  coefficients  of  digestibility  of  corn  stover  silage  fed  to 
eight  beef  cows  were  found  to  be  as  follows:  dry  substance,  54  percent; 
crude  protein,  38  percent;  nitrogen-free  extract,  56  percent;  crude  fiber, 
67  percent;  and  ether  extract,  59  percent. 

The  metabolizable  energy  of  corn  stover  silage  was  found  to  vary 
for  the  eight  cows  from  1.35  to  1.71,  with  an  average  of  1.57  therms 
per  pound  of  digestible  organic  matter.  This  value  agrees  almost  ex- 
actly with  Armsby's11  figure  of  1.588  therms  per  pound  of  digestible 
matter  obtained  from  roughages  for  ruminants. 


The  authors  desire  to  express  their  thanks  especially  to  Dr.  H.  H.  Mitchell, 
Chief  in  Animal  Nutrition,  for  his  constant  assistance  and  many  helpful  sugges- 
tions; to  R.  R.  Snapp,  Associate  Chief  in  Beef  Cattle,  for  the  supervision  of  the 
preliminary  feeding  and  handling  of  the  cattle  while  at  the  barns;  and  to  W.  T. 
Haines  for  most  of  the  work  connected  with  the  feeding  of  the  animals  during 
the  collection  periods,  the  sampling  of  feeds,  compositing,  and  preparation  of  all 
samples  for  analysis. 


482 


BULLETIN  No.  291 


[May. 


LITERATURE  CITED 

1.  TANGL,  F.,  and  WEISER,  S.    Landw.  Vers.  Sta.  74,  330.   1910-11. 

2.  BARTLETT,  J.  M.   Maine  Agr.  Exp.  Sta.  Bui.  110.  1904. 

3.  JORDAN,  W.  H,  and  HALL,  F.  H.  U.  S.  Dept.  Agr.,  Office  Exp.  Sta.  Bui.  77,  90. 

1900. 

4.  ARMSBY,  H.  P.  The  nutrition  of  farm  animals,  604.   1917. 

5.  FREAR,  WM.  Penn.  Exp.  Sta.  Rpt.,  54-68.  1890. 

6.  ARMSBY,  H.  P.   Penn.  Exp.  Sta.  Rpt.  16.   1892. 

7.  LINDSEY,  J.  B.,  HASKINS,  H.  D.,  SMITH,  P.  H.,  and  BEALS,  C.  L.  Compilation 

of  analyses.   Mass.  Agr.  Exp.  Sta.  Spec.  Bui.,  pp.  13-15.  Nov.,  1919. 

8.  ARMSBY,  H.  P.,  and  FRIES,  J.  A.  Jour.  Agr.  Res.  3,  451.  1915. 

9.  ARMSBY,  H.  P.  The  nutrition  of  farm  animals,  636.   1917. 

10.  RUBNER,  M.  Ztschr.  Biol.  21,  316,  329.   1885.  Ibid.  42,  303.    1901. 

11.  ARMSBY,  H.  P.  The  nutrition  of  farm  animals,  650.   1917. 


APPENDIX 

TABLE  A. — WEIGHTS  OF  ANIMALS  DURING  DIGESTION  TRIALS 
(All  weights  in  pounds) 


Cow  No. 

Weight  at 
beginning 
of  digestion 
trial 

Weight 
when 
placed  in 
digestion 
stall 

Weight  at 
end  of 
digestion 
trial 

Loss  in 
weight 
while  in 
digestion 
stall 

Weight 
one  week 
after  end 
of  trial 

Weight  two 
weeks  after 
end  of  trial 

Period  I 


1.  . 

1  270 

1  290 

1  215 

75 

1  320 

2  

I  315 

1  310 

1  220 

90 

1  335 

3.  .J.  .. 

1  150 

1  140 

1  110 

30 

1  160 

4.  .  .  

1  285 

1  260 

1  230 

30 

1  300 

Average  

1  255 

1  250 

1  194 

56 

1  279 

Period  II 


5.  .. 

1  135 

1  130 

1  100 

30 

1  120 

6  

1  135 

1  110 

1  080 

30 

1  155 

7  

1  035 

1  015 

990 

25 

1  060 

8  

1  260 

1  180 

1  165 

15 

1  245 

Average  

1  141 

1  109 

1  084 

25 

1  145 

TABLE  B. — NITROGEN  AND  ENERGY  TABLE 


Cow  No. 

Feed  consumed 

Dig.  carbohydrates 

Di- 
gestible 
organic 
nu- 
trients 

26s. 

Feces 

Urine 

Total 
dry 
sub- 
stance 
kg. 

Total 
nitro- 
gen 

gm. 

Energy 
therms 

Total 
kg. 

Methane 
equivalent 

Dry 

sub- 
stance 

kg. 

Total 
nitro- 
gen 

gms. 

Energy 
therms 

Total 
nitro- 
gen 

gm. 

Energy 
therms 

gm. 

therms 

Period  I 


1... 

47  5 

612 

203  9 

25  0 

1  125 

15  0 

61  4 

19  4 

307 

83  9 

355 

8.9 

2.... 

41.1 

594 

176  8 

19  7 

887 

11  8 

49  3 

18  1 

.261 

76.9 

446 

9.0 

3.. 

34  5 

522 

148  1 

17  6 

792 

10  6 

43  7 

14  9 

247 

67  4 

291 

7.1 

4  

42.0 

603 

180.1 

22.5 

1  013 

13.5 

55.9 

16.5 

.239 

70.7 

378 

8.8 

Period  II 


5... 

42.1 

617 

181  2 

19  6 

882 

11  8 

49  1 

19  1 

.290 

75.5 

274 

7.7 

6  

42  0 

621 

180  9 

19  4 

873 

11  6 

48  4 

19  6 

298 

76  8 

332 

7  6 

7  

39.7 

594 

170  8 

19  6 

882 

11  8 

49  3 

16  6 

232 

68  3 

316 

10.  1 

8  

42.4 

tilM 

182.4 

20.7 

932 

12.4 

51.9 

18.1 

.267 

73.6 

392 

8.9 

1927] 


CORN  STOVER  SILAGE  FOR  BEEF  Cows 


483 


TABLE  C. — DAILY  COLLECTION  DATA:  PERIOD  I 


Feed  offered 

Day 

Silage 

Soybean 
oil  meal 

Salt 

Water 

Orts 

Feces 

Urine 

Iba. 

Ibs. 

oz. 

Ibs. 

Ibs. 

Ibs. 

26s. 

Cow  No.  1 


1... 

50 
50 
50 
50 
50 
50 
50 

1 
1 
1 
1 
1 
1 
1 

0 
0 
0 
0 
0 

1 

1 

.13 
9.25 
24.25 
28.00 
36.63 
24.13 
24.50 

.38 
.56 
.69 
1.00 
.76 
.40 
.25 

32.75 
30.19 
35.71 
41.50 
42.40 
39.66 
39.28 

22.63 
11.46 
13.17 
12.14 
17.13 
11.36 
19.38 

2... 

3  

4  

6... 

7  

Total  

350 
50 

7 
1 

2 
.28 

146.89 
20.98 

4.04 
.58 

261.49 
37.35 

107.27 
15.32 

Daily  average. 

Cow  No.  2 

1... 

50 
45 
45 
45 
45 
45 
45 

1 
1 
1 
1 
1 
1 
1 

0 
0 
0 
0 
0 
1 
1 

24.69 
11.69 
41.88 
38.44 
47.19 
35.50 
29.19 

8.06 
7.75 
2.13 
2.75 
1.31 
1.09 
1.23 

32.56 
39.13 

42.78 
47.77 
48.98 
43.49 
47.08 

15.69 
15.88 
17.16 
22.34 
19.72 
23.22 
18.77 

2  

3  

4  

6  

7  

Total  

320 
45.7 

7 
1 

2 

.28 

228.58 

32  .  <>7 

24.32 
3.47 

301.79 
43.11 

132.78 
18.97 

Daily  average  . 

Cow  No.  3 

1... 

50 
45 
45 
40 
40 
40 
40 

1 
1 
1 
1 
1 
1 
1 

0 
0 
0 
0 
0 

1 
1 

17.94 
24.19 
35.63 
29.31 
25.94 
30.25 
28.69 

13.25 
11.75 
9.18 
5.50 
5.30 
3.94 
5.06 

36.63 
34.50 
32.86 
35.43 
40.93 
23.73 
34.20 

12.87 
7.13 
17.25 
6.81 
14.50- 
12.15 
11.44 

2 

3  

4  

5  

6  

7  

Total  

300 
42.9 

7 
1 

2 

.28 

191.95 
27.42 

53.98 

7.71 

238.28 
34.04 

82.15 
11.73 

Daily  average  . 

Cow  No.  4 

1  

50 
45 
45 
45 
45 
45 
45 

1 
1 

1 
1 
1 
1 
1 

0 
0 
0 
0 
0 
1 
1 

.06 
13.31 
20.44 
29.00 
31.00 
24.63 
21.38 

7.94 
4.00 
2.44 
1.65 
2.30 
.22 
1.00 

35.34 
35.66 
28.50 
32.61 
34.25 
37.40 
32.63 

13.88 
13.41 
12.84 
14.31 
14.45- 
17.72 
16.22 

2  

3          

4  

5  

6  

7  

Total  

320 
45.7 

7 

1 

2 

.28 

139.82 
19.97 

19.55 
2.79 

236.39 
33.77 

102.83 
14.69 

Daily  average. 

TABLE  D. — NITROGEN  BALANCE 

(All  weights  in  grams) 


Cow  No. 

Nitrogen 
in  feed 
consumed 

Nitrogen 
in 
feces 

Nitrogen 
in 
urine 

Nitrogen 
balance 

Period  I 

1.  . 

612 

307 

355 

—55 

2   

594 

261 

446 

—113 

3  

522 

247 

291 

—16 

4  

603 

239 

378 

—14 

Period  II 

5      

617 

290 

274 

+53 

6  

621 

298 

332 

—  9 

7        

594 

232 

316 

+46 

8  

621 

267 

392 

—38 

484 


BULLETIN  No.  291 


TABLE  C.  (Concluded) — DAILY  COLLECTION  DATA:  PERIOD  II 


Feed  offered 

Day 

Silage 

Soybean 
oil  meal 

Salt 

Water 

(Ms 

Feces 

Urine 

Ibs. 

Ibs. 

oz. 

Ibs. 

Ibs. 

Ibs. 

Ibs. 

CDW  No.  5 

1  

50 
50 
50 
50 
50 
50 
50 

1 
1 
1 

1 
1 
1 

1 

1 
1 
1 
1 
1 
1 
1 

15.81 
26.50 
.00 
44.44 
16.56 
26.94 
42.63 

.22 
.44 
.19 
.49 
.22 
.40 
1.13 

43.29 
39.75 
35.19 
43.19 
43.19 
42.69 
38.69 

12.20 
10.19 
19.91 
15.69 
14.31 
15.66 
12.81 

•> 

3  

4  

5  

6.... 

7  

Total  

350 
50 

7 
1 

7 
1 

172.88 
24.70 

3.09 
.44 

285.99 
40.87 

100.77 
14.40 

Daily  average  . 

Cow  No.  6 

1.  . 

50 
50 
50 
50 
50 
50 
50 

1 
1 
1 
1 
1 
1 
1 

1 
1 

1 
1 
1 
1 
1 

19.88 
28.25 
26.50 
24.69 
39.69 
23.25 
46.50 

.24 
.39 
.42 
1.24 
.63 
.90 
.60 

44.53 
37.58 
57.00 
57.33 
33.05 
56.13 
48.45 

9.58 
14.55 
14.84 
15.53 
14.30 
13.21 
15.41 

2  

.3  

4  

6  

7  

Total  

350 
50 

7 
1 

7 
1 

208.76 
29.82 

4.42 
.63 

334.07 
47.73 

97.42 
13.92 

Daily  average. 

Cow  No.  7 

1 

50 
50 
50 
50 
50 
50       . 
50 

1 
1 
1 
1 
1 
1 
1 

1 
1 
1 
1 
1 
1 
1 

.00 
.00 
26.69 
20.31 
21.75 
.00 
44.81 

.85 
1.10 
3.04 
3.43 
7.19 
2.42 
7.00 

43.36 
31.43 
23.86 
31.83 
39.15 
38.98 
28.64 

16.84 
13.63 
11.56 
18.31 
11.66 
14.75 
14.15 

2  

3  

4 

6  

7  

Total  

350 
50 

7 

1 

7 

113.56 
16.22 

25.03 
3.58 

237  .  25 
33.89 

100.90 
14.42 

Daiily  average. 

Cow  No.  8 

1.  . 

50 
50 
50 
50 
50 
50 
50 

1 
1 
1 
1 
1 
1 
1 

1 
1 

1 
1 
1 

1 
1 

24.25 
26.00 
19.00 
22.00 
26.88 
28.50 
25.63 

.18 
.19 
.17 
.13 
.23 
.21 
.09 

50.74 
36.56 
45.05 
37.88 
38.56 
38.90 
42.28 

16.03 
14.03 
17.03 
18.15 
18.00 
18.47 
15.09 

2  

3 

4  

5  

6 

7  

Total  

350 
50 

7 
1 

7 
1 

172.26 
24.61 

1.20 
.17 

289.97 
41.42 

116.80 
16.70 

Daily  average  . 

TABLE  E. — CALCULATION  OF  METABOLIZABLE  ENERGY 
(All  measurements  in  therms) 


Cow  No. 

Energy 
of  feed 
consumed 

Energy 
of 
feces 

Energy 
of 
urine 

Energy 
of 
methane 

Energy 
correction 
for  nitrogen 
balance 

Total 
metabo- 
lizable 
energy 

Period  I 

1.  . 

203.9 

83.9 

8  9 

15.0 

—  .4 

96.5 

2  

176  8 

76  9 

9  0 

11  8 

-  8 

79  9 

3  

148.1 

67  4 

7  1 

10  6 

-  1 

63.1 

4  

180.1 

70.7 

8.8 

13.5 

-.1 

87.2 

Period  II 

5  

181.2 

75  5 

7  7 

11  8 

+  .4 

85.8 

6  

180  9 

76  8 

7  6 

11  6 

—   1 

85  0 

7  

170.8 

68  3 

10  1 

11  8 

+  3 

80.3 

8  

182.4 

73.6 

8.9 

12.4 

-.3 

87.8 

UNIVERSITY  OF  ILLINOIS-URBANA 


